Mechanism of creation of compressive residual stress by shot peening

http://chglib.icp.ac.ru/subjex/2012/pdf05/InternatJHyrogenEnergy-2009-34(1)405.PDF

Carbon-based films coated 316L stainless steel as bipolar plate for proton exchange membrane fuel cells

In conventional internal combustion engines, engine valve displacements are fixed relative to crankshaft position. If these valves were actuated as a variable function of crankshaft angle, significant improvements in fuel economy could be achieved. To this end, a new type of electromagnetic valve drive system (EMVD) for internal combustion engines was more recently proposed. This EMVD incorporates a disk cam with a very desirable nonlinear profile which that functions as a nonlinear mechanical transformer. Modeling and simulation results showed significant advantages of this EMVD over previously designed electromagnetic engine valve drives. In this articles, we describe an experimental implementation of the proposed EMVD, which was developed to confirm these benefits. The EMVD apparatus was designed, constructed, and integrated into a computer-controlled experimental test stand. The experimental results confirm the benefits of using a nonlinear mechanical transformer in a motordriven engine-valve spring system, as seen in the small average power consumption and low valve seating velocity. In addition, a valve transition time sufficient for 6000-rpm engine operation was achieved. The results also suggest ways to improve the EMVD apparatus in the future.

/pdf/design-and-experimental-implementation-of-an-electromagnetic-3t22a0lqyp.pdf

Design and experimental implementation of an electromagnetic engine valve drive

A fuel cell separator comprises a resin conductive layer as a mixture of a resin and a conductive filler at least on one side of a metal substrate, wherein the resin conductive layer comprises (a) a first resin layer having a volume resistance of 10 Ω·cm or less and (b) at least one of a second resin layer constituting the surface of the resin conductive layer and having a volume resistance smaller than that of the first resin layer and a third resin layer formed in an interface with the metal substrate and having a volume resistance smaller than that of the first resin layer The separator is excellent in current collecting performance, formability, strength and corrosion resistance as a fuel cell separator, especially as a separator for a solid polymer electrolyte fuel cell

Fuel cell separator

A proton exchange membrane fuel cell stack and novel proton exchange membrane fuel cell module are disclosed and wherein the proton exchange membrane fuel cell stack includes a plurality of repeating, serially electrically coupled fuel cell stack modules, and which are sealably mounted together by a compressive force of less than about 60 pounds per square inch.

Proton exchange membrane fuel cell stack and fuel cell stack module

The gas separator is provided with a substrate portion having a predetermined concave-convex shape, an underlying coating layer formed on the substrate portion, a first coating layer for coating the substrate portion and the underlying coating layer, and a second coating layer formed thereon. The second coating layer is formed from a carbon material, and is sufficiently conductive. Moreover, the second coating layer protects the underlying layer. The first coating layer is formed from a noble metal. Therefore, the first coating layer coated with the second coating layer exhibits extremely high corrosion resistance. The underlying coating layer and the substrate portion are coated with the first and second coating layers, so that the progress in corrosion can be sufficiently prevented. Thus, excellent overall corrosion resistance of the separator can be realized.

Fuel cell gas separator, manufacturing method thereof, and fuel cell

Shot peening is one of the most effective treatments for improving the fatigue strength of transmission gears. As is well known, the improvement of fatigue strength is caused by the compressive residual stress. Fatigue crack propagation in the residual stress field was analyzed by the fracture mechanics approach, and the method for prediction of fatigue strength in terms of S-N diagrams is shown. Analytical prediction in accordance with the experimental results showed extreme delay of the crack propagation in the residual stress field, and also showed several possibilities for improving the fatigue strength by controlling the residual stress distributions.

Prediction of Improvement in Fatigue Strength by Shot Peening and Selection of Most Effective Peening Condition.

PROBLEM TO BE SOLVED: To realize enough corrosion resistance in a metal gas separator. SOLUTION: A separator 30 is equipped with a substrate 60 with a given rough shape, a base coat layer 62 on the substrate 60, a first coat layer 64 for coating them, and a second coat layer 66 fitted further on it. The second coat layer 66 is structured with a carbon material, has enough conductivity to protect the lower layers. The first coat layer 64 shows enormously high corrosion resistance being covered with the second coat layer 66, because it is formed of precious metal. The base coat layer 62 and the substrate 60 are covered with the first coating layer 64 and the second coat layer 66, so that progress of corrosion can be prevented, and the whole separator 30 shows good corrosion resistance.

Fuel cell gas separator, manufacturing method of fuel cell gas separator and fuel cell

The shot velocity in two pneumatic shot-peening machines has been examined by means of experiment and theory. The shot velocity was measured under various operating conditions by a high-speed shutter TV camera. As a result, the shot velocity over the usual range of shot diameter D, shot density p, and air-pressure p was related by the formula, V=K·Dα·ρβ·(p+pb)γ, where Pb is atmospheric pressure. α and β are almost independent of the shot-peening machine, and α a 0.36, β a 0.48, K and γ are dependent on the shot-peening machine. On the other hand, the theoretical consideration based on hydrodynamics tied to the derivation of the formula, V=K·D-0.44·ρ-0.44·(p+pb)0.43 for the suction type machine, and almost the same formula for the direct-pressure type. The theoretically derived formula coincided well with the experimentally induced formula.

Measurement and Analysis of Shot Velocity in Pneumatic Shot Peening.

An endless metallic belt has at its outer peripheral surface a layer provided with a compressive residual stress by shot peening, and also has at its inner peripheral surface a layer provided with a compressive residual stress by shot peening. In a method for manufacturing the endless metallic belt, both outer and inner peripheral surfaces of the endless metallic belt are subjected to shot peening, wherein the inner peripheral surface is shot peened prior to the outer peripheral surface. The method produces an endless metallic belt having its fatigue strength improved without suffering any significant deformation.

Hideo Aihara

Papers

Fuel cell gas separator, manufacturing method thereof, and fuel cell

Prediction of Improvement in Fatigue Strength by Shot Peening and Selection of Most Effective Peening Condition.

Fuel cell gas separator, manufacturing method of fuel cell gas separator and fuel cell

Measurement and Analysis of Shot Velocity in Pneumatic Shot Peening.

Endless metallic belt and manufacturing method therefor